1. Performance measurement with the alternate marking method in SFC draft-mirsky-sfc-pmamm-01
Greg Mirsky
Giuseppe Fioccola
Tal Mizrahi
IETF-99 July 2017, Prague

2. What and why
|Ver|O|R| TTL | Length | M |R|R|MD Type| Proto | Mark field |S|D| S – single mark method D – double mark method

3. Single Mark Method
Batching packets based on time interval to measure packet loss by switching value of the S flag. D flag MUST be set to 0 on transmit and ignored on receipt.
First/Last Packet Delay calculation:
capture timestamp of when S flag value flips. Method is sensitive to packet loss and packet re-ordering
Average Packet Delay calculation:
collect timestamps for each packet received within a single block. Average of the timestamp is the sum of all the timestamps divided by the total number of packets received. Hence minimally impacted by a packet loss and no impact if packets get re-ordered.
Average Delay Variation calculation is possible
S=1
S=0
S=0
S=1
S=1
S=1
S=0

4. Double Mark Method
Use S flag to create batch of packets as in Single Mark method
Use D flag to create new set of marked packets that are fully identified over the BIER network
Collect and compare timestamps on D-marked packets to calculate more informative one-way packet delay metrics, such as minimum, maximum delay, median and percentiles values.
Double mark method may be implemented by multiplexing fields or making certain assumptions about characteristic information that identifies the flow. More information can be found in draft-mizrahi-ippm-multiplexed-alternate-marking-02
S=1, D=0
S=0, D=1
S=0, D=0
S=1, D=0
S=1, D=1
S=1, D=0
S=0, D=0

5. PMAMM Applicability The Classifier marks packets
Measurement Point at SFF3 enables e2e Packet Loss measurement, efficient measurement of Mean (Average) Delay and full spectrum of timing metrics, e.g. minimum, maximum, median delay values, delay variation
Measurement Point may be dynamically enabled at any of the SFC entities, e.g. any combination of SFs and/or SFFs, to localize service degradation
SF1
SF1’
SF2
SF3
SF3’
Classifier
SFF1
SFF2
SFF3

6. Next Steps Welcome questions, comments Address comments Adopt by WG
Thank you